High Pressure Expansion Joints Built for MHI Petrochemical Project
When Mitsubishi Heavy Industries (MHI) needed high pressure
gimbal and hinge expansion joints for recycle gas compressors
for their client, Mitsubishi Petrochemical, sources
inside and outside of Japan were inquired. The restrictions
imposed by the Japanese High Pressure Gas Control
Law204 and the High Pressure Gas Safety Institute of Japan
(also known as KHK) required that the expansion joints
be proof tested to 4 times the operating pressure.
The pressure ratings for the lot of 11 expansion joints ranged
up to 607 psig (42.5 kg/cm2) for operating, 2428 psig (170
kg/cm2) for proof test. All the expansion joints were designed
with hinge, gimbal or tie rod restraint hardware that had to
contain the pressure thrust generated at the design pressure
and at the hydrostatic test condition. For the largest
expansion joints (36" gimbal units), the pressure thrust
force at the design condition was 706,000 pounds (321,000
kg).
The design was further complicated by the fact that the bellows
were to be ply testable. Each bellows was fitted with
two ply testable connections located 180 degrees apart on
opposite ends of the bellows. To provide proof that the ply
testable pressure taps would sense an inner ply leak during
operation, it was necessary to establish a measured
flow rate between the ply testable connections while the
bellows were at the hydrostatic test pressure condition.
In addition to the challenging technical requirements, it was
absolutely essential that all design drawings, design approvals,
prototype tests and finished hardware be produced
in 4 months time. It was a difficult decision for MHI to place
such a complex order for critical path material with a foreign
company.
The expansion joints were produced on time to the complete
satisfaction of MHI and the KHK inspector. Mr.
Takayama, the quality assurance manager at MHI in Tokyo
who was sent to inspect the parts at Senior Flexonics Pathway
commented, “The quality of welding that he witnessed
at Senior Flexonics Pathway was excellent”. The KHK inspector,
Mr. Yamashita was also very pleased with the quality
he witnessed at Senior Flexonics Pathway.
To inquire about high pressure expansion joints for any
critical application, contact: Senior Flexonics Pathway.